Field of the Invention
The present invention relates to an exhaust emission control device for an internal combustion engine, which supplies secondary air to an exhaust system.
Description of Related Art
For example, Japanese Patent Application Publication No. Hei 9-324624 (FIGS. 1 to 5) shows an exhaust emission control device for an internal combustion engine, which introduces secondary air into an exhaust port by opening reed valves provided to a cylinder head portion by using exhaust pulsation pressure. This publication shows a structure where two reed valves are arranged side-by-side and covered with one reed valve cover.
However, since the multiple reed valves are arranged side-by-side, the structure shown in Japanese Patent Application Publication No. Hei 9-324624 (FIGS. 1 to 5) makes the reed valve cover for covering the reed valves become larger in size, and accordingly may make it difficult to lay out the reed valve cover in the cylinder head portion.